Hydrion Chlorine Test Paper provides a simple, reliable, and economical means to measure the concentration of free available chlorine in sanitizing solutions. With color matches at 10-50-100-200ppm, the test paper measures concentrations between 10-200ppm. Federal, State and Local health regulations require users of chlorine-based sanitizer solutions to have appropriate test kits available to verify the strength of sanitizer solutions. Sanitizer solutions are essential in the food service industry to ensure that sanitizers are at the proper concentration specified by the individual manufacturer. With color matches at 10-50-100-200ppm, the test paper measures concentrations between 10-200ppm. 25 strips per package.